This invention relates to a device for forming an initial bight of a roving around a slubbing bobbin in an automatic textile winding machine such as a roving frame, a flyer frame, an intersecting or the like of the kind comprising a horizontal rotary driving cylinder adapted for said slubbing bobbin to rest thereon and to be driven thereby, a roving guide actuated to be driven with a longitudinal reciprocating movement adjacent to the generatrix of contact of the slubbing bobbin and of the driving cylinder.
The automatic bobbin changing mechanisms generally operate in three phases, namely : ejection of a full bobbin, introduction of a new slubbing bobbin, and applying, to said new slubbing bobbin, the new end of the roving formed by breaking of the roving upon the ejection of the full bobbin. It is this last phase, in which the newly formed end of the roving is applied to the bobbin for starting the winding thereof, which the present invention proposes to improve.
In known mechanisms of the kind with which this invention is concerned, the leading end of the roving is presented freely to the slubbing bobbin and is formed in a loop thereover, for example, by a plate; thereafter the leading end is taken up in a more or less reliable manner by the nip between the driving cylinder and the slubbing bobbin, which has more especially the following disadvantages :
Since the roving end is free, that is to say that it is in no way controlled relative to the slubbing bobbin, its presentation to the nip is somewhat random, and it may arrive thereat in the least practical position in which case it may cause faulty winding, or clogging or obstruction of the bobbin and/or driving cylinder; accordingly, large losses of material can occur and considerable time is involved in manual rectification. It may also present itself crosswise or transversely at the side, or in any disadvantageous position, so that the member provided therefor may not always form a bight off the roving around the slubbing bobbin, which has the disadvantages already mentioned and results in untimely stoppages of the machine.
When the roving end is formed in a loop or bight around the slubbing bobbin, there is still a risk that it will not be taken up and entrained by the driving cylinder and the slubbing bobbin, which may also result in jamming, machine stoppages, losses of material and even the production of defectively-wound bobbins.
An object of the invention is to provide a device for forming an initial bight around the slubbing bobbin, with the leading end of the roving at the start of winding, which does not have the above-discussed disadvantages of the known devices.
With this object in view, the present invention provides a device for forming an initial bight of a roving around a slubbing bobbin at the commencement of winding, in an automatic textile winding machine, such as a spindle frame, an intersecting comber or the like, comprising a driving cylinder adapted for said slubbing bobbin to rest thereon and to be driven thereby, a roving guide adapted to be driven with a longitudinal reciprocating movement adjacent to the generatrix of contact of the slubbing bobbin and the driving cylinder, and pneumatic blowing means for applying the leading end of the roving to the slubbing bobbin, said device being characterised in that it comprises a suction nozzle for said leading end of the roving and situated substantially at the level of said generatrix of contact at a spacing from said generatrix to the downstream side relative to the direction of rotation of said driving cylinder, and a bight-forming finger disposed parallel to said generatrix and adapted to oscillate, parallel to itself, between a rest position below the space between said generatrix and said suction nozzle, and an operative position in which it is located above and behind said slubbing bobbin, having entrained with it said roving end in passing from its said rest position to its said operative position, said finger having at least one air jet which, when said bight-forming finger is in its operative position, is directed towards the nip between said driving cylinder and said slubbing bobbin, behind the latter, that is to say at the upstream side thereof, and which jet is then connected temporarily to a source of compressed air.
With such a device, upon the loading of a fresh bobbin, an extra length of the roving is caused to protrude from the nip between the driving cylinder and the bobbin, by reason of the roving being jerked forward by the bobbin, and this extra length extends to and is drawn out taut by the suction nozzle. The bight-forming finger, in its ascending movement from its lower position of rest, encounters the roving end held taut in this way and forms it into a loop or bight around the slubbing bobbin. At the end of the travel of the finger, when it is located above and behind said slubbing bobbin, its jet is fed with compressed air so as to blow the free end of the roving into the nip between the driving cylinder and the slubbing bobbin, at the side upstream of the generatrix of contact, so that the roving end is taken up and entrained between the driving cylinder and the slubbing bobbin. Taking account of the fact that, during the work cycle of the bight-forming finger, the roving guide shifts from one end to the other of the slubbing bobbin, it will be appreciated that the portion of roving delivered by the roving guide at the end of the cycle overlies the leading end portion of the roving; accordingly, tight turns are formed around the bobbin, these gripping tightly around the slubbing bobbin, which is particularly favourable for reliable starting of the winding of the roving.
Such an embodiment has a whole series of advantages :
Since the roving end is taut, it always presents itself in the same way, and correctly, to the slubbing bobbin, which reduces the risk of slippage and of jamming and accordingly results in a considerable saving of material and time for personnel. The result is an increase in the efficiency of the machine.
Since the roving end is controlled relative to the slubbing bobbin, because it is tautened, it always occupies a precise position and the bight-forming member is always capable of forming the roving into a bight around the slubbing bobbin, which avoids stoppages of the machine.
Because of the air blown through the jet of the bight-forming finger, the roving end is always reliably positioned between the driving cylinder and the slubbing bobbin, so that it is taken up in a reliable manner and always entrained thereby, which yet again eliminates causes of jamming, stoppages of the machine, losses of material, and the risk of producing defectively-wound bobbins.
By reason of the precise movements executed by the components of the device of the invention and because their positions are well defined and constant, the roving end always occupies the same position, which makes the machine very reliable.
The combination of the action of the roving bight-forming finger and of the movement of the roving guide ensures the formation of a bight and then of overlaid turns of the roving around the slubbing bobbin, which further increases the reliability of the machine.
In an advantageous embodiment, a horizontal table extends from adjacent the generatrix to said suction nozzle and the bight-forming finger, in said position of rest, is withdrawn beneath said table, through an opening in the latter. Thus, at the start of each winding cycle, the roving end, fed out by the driving cylinder and drawn taut by the suction nozzle, rests on the table while sliding thereover, which improves the precision of its positioning and facilitates its engagement by the bight-forming finger.